A police investigation into the death of a man in Michael Barrymore's swimming pool may have been hampered by a Home Office pathologist's failure to spot crucial evidence, BBC Radio Four's File on 4 will reveal this week.

An investigation by the programme has also found the pathologist, Michael Heath, has been criticised for omissions in previous cases.

Dr Heath was brought in when Stuart Lubbock was found dead at the entertainer's Essex home in April last year.

He concluded the 31-year-old had drowned.

An open verdict was recorded into Mr Lubbock's death

But three other pathologists told the inquest into his death this month that marks on his face indicated he died of asphyxia, possibly from having an arm clamped round his throat during a violent sexual assault.

In the days after Mr Lubbock's death, police believed he died as a result of a tragic accident.

Now the barrister who represented the Lubbock family at the inquest, Matthew Gowen, has told File on 4 the investigation might have reached a different conclusion if the evidence of throttling had emerged sooner.

"The police weren't aware that asphyxia may have been something they should have been pursuing.

"They did all they humanly could to investigate the case, but it wasn't for some weeks they went back to Mr Barrymore's house and did a very thorough second examination when they took many items away to be forensically examined.

"Clearly that was as a result of further reports they got as the process went on which they hadn't had initially," he said.

Growing workload

The programme will also look at other cases in which Dr Heath's findings have been questioned.

Steven Taylor, a traveller, spent 10 months on remand facing a charge of murder after Dr Heath said he had strangled his wife.

But two other pathologists concluded that marks on Beatrice Taylor's neck were caused by procedures carried out by a mortuary technician.

Kenneth Fraser was accused of killing his girlfriend after Dr Heath said she had been hit on the head with a plank of wood, but was released after four other pathologists found she had fallen downstairs.

Dr Heath has declined to give an interview to the programme, but it is understood he stands by his findings in all the cases.

The programme will focus on a deepening crisis in the forensic pathology profession which has been exacerbated by growing workloads of cases and by a shortage of new recruits.

The Home Office is currently reviewing the way forensic pathology is organised in England and Wales.